Biomedical subjects

An-Long Xu

Publications and source records attributed to An-Long Xu.

24 records · Page 2Linked to original sources

PubMed2002

[The construction of cDNA expression library from the tentacles of Sagartia rosea].

A cDNA expression library of the tentacles of Sagartia rosea was constructed. The cDNA was cloned into eukaryotical expression plasmid pcDNA3. SMART protocol was used for cDNA library construction and bioinformatics analysis was carried out. 71 novel EST clones were obtained from 130 sequences in the library, of which there were 21 full-length clones, including cytolysin genes, flourescent protein, ubiquinol-cytochrome C reductase gene, elongation factor, ferritin gene riboflavin kinase gene, ribosomal protein. This provides a base for further investigating their biological activity and application.

Animals↗

PubMed2002

[Determination of HLA-DRB1 gene polymorphism by PCR-SBT in Lahu ethnic group of Yunnan, China].

The HLA-DRB1 gene polymorphism in Lahu ethnic of Yunnan, China was the first time investigated using high resolution PCR-SBT method, which is based on sequences of HLA-DRB1 Intron 1 and Intron 2 and with our improvement. From 55 individuals of Lahu ethnic 16 DRB1 alleles were detected. The three most common alleles were HLA-DRB1 * 12021(30.909%), 09012(15.455%), 15011(13.636%), and they covered 60% of the total alleles detected from Lahu ethnic.HLA-DRB1 * 1413, * 11081, * 1312, * 1418, * 1504 were the first time detected in the Chinese, and were very rare in worldwide ethnic groups. With comparison of HLA-DRB1 gene frequencies between various ethnic groups we analyzed the characteristics of HLA-DRB1 gene distribution in worldwide populations,and constructed the phylogenetic tree by Neighbor-joining method and Nei measure of genetic distance. The result showed Lahu ethnic obviously belong to the Chinese South ethnic groups and can't trace its origin from northern groups with the HLA-DRB1 genetic data. The preliminary explanations about the contradiction were given in this paper.

English Abstract↗

PubMed2001

Identification and Funtional Characterization of Three Postsynaptic Short-chain Neurotoxins from Hydrophiinae, Lapemis hardwickii Gray.

Three cDNA clones, sn12, sn36 and sn160, encoding isoforms of postsynaptic short-chain neurotoxins, were cloned by screening a cDNA library of the venom from Hydrophiinae, Lapemis hardwickii Gray. The sequences of three cDNA clones encoded proteins consisting of 60 amino acid residues. There was only one amino acid substitution among the three isoforms SN12, SN36 and SN160 at the position 46 of mature proteins, and they were Pro(46), His(46) and Arg(46), respectively. The three molecules were expressed in Escherichia coli and the recombinant proteins were characterized. Different LD(50) were obtained, namely 0.0956 mg/kg, 0.3467 mg/kg and 0.2192 mg/kg, when the SN12, SN36 and SN160 were injected into Kunming mice(i.p.). In analgesic effect assayed by the acetic acid-induced writhing method, SN12 and SN160 showed similar analgesic effect, but SN36 had effects significantly different with the other two. Our studies suggested that the amino acid residues on position 46 could affect the combination between the postsynaptic short-chain neurotoxins and the nicotinic acetylchoine receptor, since different amino acid substitution resulted in different biological activities.

Journal Article↗

PubMed2001

Diversity of PLA(2) Genes from Sea Snake Lapemis hardwickii Gray Venom.

Three full-length cDNA from Lapemis hardwickii Gray, (namely PLA(2)-8, PLA(2)-9 and PLA(2)-384), encoding phospholipase A(2) (PLA(2)), were isolated and sequenced. These cDNA sequences were composed of 456 bp, 438 bp and 438 bp, encoding a signal peptide of 27 amino acids and a mature peptide of 125, 119 and 119 amino acids, respectively. The analysis results by computer indicated PLA(2)-8, PLA(2)-9and PLA(2)-384 has a pI of ca. 4.8, 7.8 and 8.4, respectively. Sequence analysis of amino acid and prediction of secondary structure suggested that these isoforms of PLA(2) belong to class I PLA(2) family. PLA(2)-8 was highly homologous (81%) to Notechis scutatus scutatus (Australian tiger snake) PLA(2), PLA(2)-9 and PLA(2)-384 showed fairly high sequence homology (90%) to Enhydrina schistosa (beaked sea snake) PLA(2), indicating that they might have similar functions. These results reflect the diversity of Lapemis hardwickii Gray PLA(2) genes. The successful cloning of these isoenzyme genes of sea snake PLA(2) may provide new information for the study on structure-function relationship of PLA(2) family and its possible molecular mechanism.

Journal Article↗

PubMed2001

Effects of Cyclosporine A and Highly Expressed Bcl-2 on Apoptosis of HL-60 Cells Induced by EGTA.

Effects of mitochondrial permeability transition pore-specific inhibitor cyclosporine A (CsA) and highly expressed Bcl-2 on the apoptosis of HL-60 cells induced by EGTA were studied. Detection of apoptotic peak by flow cytometry, fluorescent microscope observation of chromatin condensation with double staining of PI and Hoechst33342 and DNA ladder analysis all demonstrated that CsA obviously enhanced the apoptosis of HL-60 cells induced by EGTA, while highly expressed Bcl-2 completely blocked it. It is revealed by mitochondrial membrane potential (deltapsi(m)) fluorescent probes rhodamine 123 and CMXRos that the deltapsi(m) decreased in the apoptosis of HL-60 cells induced by EGTA. CsA enhanced the decrease of deltapsi(m), but highly expressed Bcl-2 increased deltapsi(m) of HL-60 cells about 2-fold and completely blocked the decrease of deltapsi(m).

Journal Article↗

PubMed2001

Effect of recombinant human interleukin-10 on the in vitro proliferation of rat vascular smooth muscle cells.

OBJECTIVE: To observe the effects of recombinant human interleukin-10 (rhIL-10) on the proliferation of rat vascular smooth muscle cells (VSMCs) cultured in vitro. METHOD: Aortic VSMCs cultured in vitro were treated with varied doses of rhIL-10 alone or in combination with tumor necrosis factor-alpha (TGF-alpha) or platelet-derived growth factor-BB(PDGF- BB) respectively. The VSMC proliferation was quantified by colormetric assay. RESULTS: Compared with control, both TNF-alpha and PDGF-BB stimulated conspicuous proliferation of VSMCs, but the effect of which was not observed by rhIL-10 treatment alone. In the presence of rhIL-10, the proliferation effects of both TGF-alpha and PDGF-BB on VSMCs were significantly inhibited (P<0.05). CONCLUSION: rhIL-10 can inhibit VSMC proliferation induced by TNF-alpha and PDGF-BB, thus may provide a new therapeutic approach for regulating vascular wall remodeling after vascular injury.

Journal Article↗